All are great, but in my opinion nothing matches Vice City. It was just so perfect. The animations, the sound...running the computer program via DOS with "Video Killed the Radio Star" playing in the background...it just felt so perfect. Vice City has the best presentation and style of any game ever created. Impeccably done on all fronts...

...that said, R* is the master of this in all of their games. I was listening to the GTAIII opening theme while typing up this response and couldn't help but think "damn, this is so good too" haha.